Coated fiber strands can be used in making a variety of products. For example, optical fibers typically comprise a fiber optic strand having one or more resin coating layers which protect the fiber from environmental conditions such as dust and moisture that can adversely effect its properties.
Examples of multiple coating layers for optical fibers are disclosed in U.S. Pat. Nos. 4,480,898; 4,474,830; 4,851,165; and 5,146,531 each of which are incorporated by reference in their entirety for all purposes.
These coating layers often include a first, or primary, coating layer directly applied to the glass fiber, which acts as a "buffer" to cushion and protect the fiber, and a secondary coating layer. The secondary coating layer typically functions as a protective outer layer preventing damage to the fiber during processing and use.
Because optical fiber coatings are typically clear, the resulting optical fiber is not colored. However, it is known to provide a colored coating and therefore a colored optical fiber. In this regard, a desired color is mixed into the prepolymer containing composition that forms the desired coating. This colored coating is then introduced as a substitute for the secondary coating or as an additional tertiary coating onto the fiber.
While this technique has allowed for the "coloring" of fibers, it has introduced its own set of difficulties. For example, in processes which seek to cure both the primary and secondary coatings in a single curing step, the use of a colored secondary coating can adversely effect the cure of the inner or primary coatings and thus, lead to poor mechanical performance of the fiber.
Moreover, from a practical standpoint, insofar as a manufacturer must maintain a separate inventory for each of the colored coatings, inventory management is more complicated. For example, at least twelve different colors are employed in the field of telephony. Accordingly, to provide color fibers for use in such environments, manufacturers would be required to maintain a separate inventory for each of the desired colored secondary coatings.